Electron transport in percolating gold films

Thin gold films with thicknesses below t=10 nm condensed at T=300 K onto amorphous carbon layers exhibit large channel structures which increase in size approaching the percolation threshold for p>p(c). The topographies of the percolating films show fractal properties as obtained from direct analysis of electron micrographs. For the same films we carried out magnetoresistance (MR) measurements at low temperatures (50 mK<T<30K) and compared these data with those from gold films with no voids or channels (t>10 nm). For both films we find the phase coherence length below 0.5 K to be temperature independent which we interpret as arising from spin scattering at magnetic impurities.